/Engine/Plugins/FX/Niagara/Source/NiagaraEditor/Public/NiagaraGraph.h
Synchronize all the properties of DestScriptVar to those of SourceScriptVar, as well as propagating those changes through the graph (pin variable names and default values on pins.) If DestScriptVar is not set, find a script variable with the same key as the SourceScriptVar. Returns bool to signify if DestScriptVar was modified.
bool SynchronizeScriptVariable ( const [UNiagaraScriptVariable](API\Plugins\NiagaraEditor\UNiagaraScriptVariable) * SourceScriptVar, [UNiagaraScriptVariable](API\Plugins\NiagaraEditor\UNiagaraScriptVariable) * DestScriptVar, bool bIgnoreChangeId )